Conventional tape drives can erase data that has been previously written by using the write head elements of the native read/write head. Such data erasure could be simply a matter of overwriting every track of data with moot information or with DC or AC erasure signals. However, due to the limited number of data channels in a native read/write head and the extremely narrow track widths, using the standard native read/write data heads as found in a conventional drive configuration would take an overwhelming amount of time to erase one tape cartridge. Consequently, more efficient erase schemes have been developed which use specific erasure hardware including an erase head that can erase many data tracks at one time.
For example, many disclosures have been made on the reuse of data tape by erasing and recertifying the data tape, and some efforts have been commercially successful. However, in ultra-secure environments charged with the safekeeping of sensitive data, such as but not limited to bank account information or other private consumer, commercial, or governmental information, these techniques are lacking in their forensic attributes. In particular, data tracks un-erased by such systems remains on the tape.
Some examples of data erasure techniques in use today include open loop systems that erase most, but not all, of the data in the data bands. One system uses a custom designed ferrite magnetic recording head, and another system uses a permanent magnet erase head. In both systems, the width of the erasure head element is less than that of the associated data band. In both of these systems, the erasure technique leaves many data tracks un-erased. These un-erased data tracks are the outermost tracks of the data band and are the data tracks near to or adjacent to the servo bands on either side of the data band. The permanent magnetic erase head also suffers from the fact that it is always on, it is not controlled by a writing coil, and cannot have well controlled edges which in combination with write current can produce a known and reproducible track edge condition.
In general, current open loop erase systems on the market are notorious for leaving 10 to 100 micron wide strips of data bands un-erased, as they would otherwise risk damage to the servo bands, thereby making the tape unusable. The reason for this lack of complete erasure is that the erase heads are not made to precisely match the data band width, and even if made precisely so, the placement of the heads is imprecise. These remnant data band regions are generally adjacent to the servo bands. As a result of the higher areal densities on the most current tape cartridge products, these remnant strips contain more and more information that is left un-erased and open for discovery. This is a significant security issue if a data cartridge is to be redeployed for use by another customer, or for use with another customer's data. Using the current deployed technology of open loop data erase systems, more and more files can be discovered and risk being transmitted to unintended parties. In short, an open loop control combined with the necessarily under-width erase gaps will result in remnant data tracks adjacent to the servo band boundaries.
In order to improve upon this, closed loop erasure schemes have been proposed. However, the conventional closed loop systems lack specific erasure methods to be employed as well as mechanical designs of the apparatus to perform each particular method. The most simplistic of the closed loop methods published teaches the use of one erase element for each data band, but does not speak to the fact that all servo information is localized to a particular data band and further ignores the tolerance stack ups inherent in a data cartridge media.
In part, due to the deficiencies of the techniques previously disclosed, and in part due to the lack of precision in implementing such techniques, there exists a need to implement a novel and robust data erasure system. There further exists a need in the art for a closed loop data erase system with a precision erase head and a precision erase head that enables such a closed loop procedure.